Tip sharpening machine for drills, especially twist drills

ABSTRACT

A machine for sharpening drills, especially twist drills, in which a pair of grinding discs are mounted in adjacent relation and rotate on respective axes which are parallel and offset so the discs define a re-entrant grinding throat. A drill holder is provided to support a drill so the point end can be introduced into the grinding throat at an angle. The drill holder includes means to adjust the drill axially and angularly and can move the drill from grinding position to an inspection position wherein a microscope is located and which includes hairline means for precise adjustment of the drill in the drill holder.

United States Patent Weng 1 Aug. 13, 1974 [54] TIP SHARPENING MACHINE FOR DRILLS, 2,017,532 10/1935 Elter et a1. 51/219 R ESPECIALLY TWIST D S 2,474,357 6/1949 Haynes 51/219 R X 2,618,909 11/1952 Hill 51/96 X Inventor: Georg Ernst g, Ravensburg, 2,827,741 3/1958 Hillier 51/219 R Germany 2,897,635 8/1959 Stephanoff.. 51/84 R 2,907,149 10/1959 Wjt es el 51/219 R [73] Asslgneel Halve 1 2,911,771 11/1959 Amiet 51/219 R Kommandltgesellschaft fizg gfi g gg izgggg g Primary ExaminerHarrison L. Hinson y Attorney, Agent, or Firm-Walter Becker [22] Filed: Feb. 15, 1973 [21] Appl. No.: 332,616 [57] ABSTRACT A machine for sharpening drills, especially twist drills, [30 F i Application priority Data in which a pair of grinding discs are mounted in adja- Feb 17 1972 Germany 7205920 cent relation and rotate on respectlve axes WhlCh are l5l973 German parallel and offset so the discs define a re-entrant grinding throat. A drill holder is provided to support a U S R R 5 R SO the point end Can be introduced into the grind- [51] g 7/00 B2lk 3/10 ing throat at an angle. The drill holder includes means [58] Fie'ld 51/219 R 84 R to adjust the drill axially and angularly and can move 51/85 R 4 6 the drill from grinding position to an inspection position wherein a microscope is located and which in- [56] References Cited cludes hairline means for precise adjustment of the UNITED STATES PATENTS drill in the drill holder.

12 Claims, 10 Drawing Figures 288,069 11/1883 Landers ..51/219R PAIENTED Am: 1 31974 SHEET 1 OF 6 L M m 3W name 50 AUG! SHE PATENT PAIENTED AUG 1 3IS'I4 3, 828,480

SHEET 3 OF 6 PAIENIEB we 1 31974 SHEET B [)F 6 TIP SHARPENING MACHINE FOR DRILLS, ESPECIALLY TWIST DRILLS The present invention relates to a tip sharpening machine for drills-especially for twist drills, with a drill holding device and with at least one rotatably mounted machining tool for instance a diamond-grinding disc which are movable toward each other in a feeding device and are mounted in a machine frame.

It is an object of the invention so to design a machine of the above mentioned type that in spite of a simple construction a precise and fast sharpening of the drill tip will be assured.

This object will be realized by a tip sharpening machine according to the present invention by providing at least two machining tools having their axes offset with regard to each other in such a way that when viewing in feeding direction they will in at least one position with their working surfaces form a re-entrant machining zone for contact with the drill tip or drill point. 'In this way, in one single working step, two free surfaces arranged at an angle to each other and around the drill axis located one behind each other of a cutting edge of the drill can be machined.

It is also possible that the axes of the sharpening tools are located at an angle with regard to each other, for instance at a right angle. A particularly simple construction, however, is obtained when the sharpening tools are mounted in an axes-parallel manner preferably rotatable about horizontal axes and are vertically offset with regard to each other.

In order to be able in a simple manner to influence the angle and the location and magnitude of the respective free surfaces, the two sharpening tools are located on separate head stocks of which at least one head stock, especially two head stocks, are adjustable for varying the re-entrant maching zone. In particular, it is expedient in this connection when the adjustable head stock is adjustable approximately at a right angle with regard to the central plane of the re-entrant machining zone which is parallel to the feeding direction, and/or parallel to said centralv plane and at a rectangle to the feeding direction while preferably both head stocks are adjustable parallely with regard to each other so that various adjusting possibilities are assured. With a simple embodiment of the invention, the adjustable head stock is mounted on a carriage guide parallel to the central plane of the machining zone while preferably both head stocks are mounted on the same carriage guides. For purposes of obtaining a compact construction, the two sharpening tools are arranged directly adjacent to each other while preferably the head stocks are located on those sides thereof which face away from each other.

For purposes of obtaining a still faster machining of the drill, each sharpening tool is formed by at least two, especially three individual tools arranged in series in feeding direction for coarse, fine and finest machining while for instance each sharpening tool comprises three individual discs of different coarse diamond grain. Expediently, the individual tools of each sharpening tool are located adjacent to each other and are combined to a preferably disc-shaped tool body.

Both sharpening tools may in a simple manner'be drivingly connected to a common motor which preferably is located on that side of the tool axes which faces away from the machining zone and is axis-parallel to said tool axes so that the motor will not interfere in any way. A further simplification in the construction of the machine is obtained when on those sides of the head stocks which face away from each other, and more specifically, on the working spindles of said head stocks, there are arranged pulleys or the like which are drivingly connected with output discs or the like which are arranged on both ends of the motor shaft. Such a driving connection may for instance be established by V- belts.

In order to assure that the drill cutting edge can be aligned in a simple manner relative to the sharpening tools, the holding means for the drill is adjustable about the central axis of said holding means and/or is adjustable in the direction of said axis and is also adapted to be arrested in its desired position. For purposes of obtaining a favorable free angle or front clearance angle, the central axis of the drill holding means is in sharpening position inclined to the central plane of the machining zone which is parallel to the feeding direction and- /or is inclined to the feeding direction. If the drill holding means is adjustable about an adjusting or setting axiswhich is at a right angle to the central plane of the machining zone which is parallel to the feeding direction and is arrestable in its respectiveposition, it is possible in spite of a simple adjustability to machine or grind any desired front clearance angles.

For further simplifying the handling of the machine according to the present invention, there is provided an abutment for the drill tip which in at least one position islocated opposite the front end of the drill holding means so that the drill also in its longitudinal direction can be adjusted in a simple manner but precisely for the machining position.

In this connection, a simple construction will be obtained when the abutment for the longitudinal movement of the drill is movable from its abutment position located in front of the drill holding means in grinding position into a downwardly located grinding position and in particular is pivotable about an axis arranged in spaced relationship to the abutment surface and parallel to the drill holding position when in grinding position. In this way, the axis of the drill is already when longitudinally aligning the same occupying its grinding position so that the drill holding means after carrying out the longitudinal alignment of the drill can be left in this position for purposes of grinding.

Expediently, the drill holding means is mounted on a bearing block which is pivotable about the setting axis in conformity with a scale and is arrestable in this position so that in spite of a simple adjustability a very compact construction will be obtained. During the drilling operation, the drill can be fed or advanced in a simple manner when the drill holding means is provided on a carriage which is mounted parallely with regard to the axis of the drill holding means occupying the grinding position, preferably is journalled on the bearing block. A very simple construction is assured when the drill holding means is pivotable relative to the carriage substantially exclusively about its axis and/or about the aligning axis. Furthermore, according to the present invention, between the mounting of the drill holding means in grinding position and the machining zone there is provided an aligning device for the drill holding means and/or for the drill while the respective aligning device is preferably formed by a prism which is open toward the central plane of the machining zone, which central plane is parallel to the feeding direction so that while the drill holding means or the drill can be introduced in a simple manner, a safe support will be assured.

In order to be able to align the drill in the sharpening position still easier, the drill holding means is pivotable about an aligning axis which is parallel to the central plane of the machining zone, which central plane is parallel to the feeding direction, said parallel aligning axis preferably intersects at a right angle the axis of the drill holding means.

In order to be sure that the drill during the sharpening operation can be supported with still greater safety and precision, the aligning arrangement when viewed in feeding direction is displaceably mounted at an angle which closes toward the machining zone with regard to the axis of the drill holding means in grinding position. This adjustability may preferably be effected by a square shaft.

The aligning arrangement for the drill holding means which, inasmuch as it has not to be associated with any different diameters may be non-adjustably or rigidly arranged and expediently is closer to the machining zone than the adjusting axis, preferably it is located in the center between said adjusting axis and the machining zone, whereas the aligning arrangement for the drill is located directly adjacent to the machining zone and thus practically supports the drill at its tip.

A further simplification in the construction of the machine according to the invention is obtained when the aligning arrangement and the mounting for the drill abutment in the longitudinal direction of the latter as well as the aligning axis are located on the carriage. The invention is furthermore characterized by a microscope the inlet side of the objective of which is at least in one position located opposite the front end of the drill holding means. This microscope is preferably an angle microscope while the inlet axis is approximately parallel to the drill holding means in grinding position. In this way, the adjustment of the drill about its longitudinal axis, which adjustment requires the proper position of the cutting edges relative to the sharpening tools, is considerably facilitated, particularly when drills of a small diameter of for instance from 0.2 to 4 millimeters diameter are to be sharpened for which the machine according to the invention is particularly suitable. A still simpler alignment is obtained when the microscope has a goniometer head with crossing hairlines and preferably with central circles.

In order to be able to adjust the microscope with its inlet axis precisely parallel to the axis of the drill holding means in grinding position, the microscope may be adjustable about a setting axis which is located approximately in the feeding direction and preferably intersects with the inlet axis approximately in the inlet plane, and is adjustable in its respective position so that the inlet range of the microscope will during the adjusting movement always remain within the region of this adjusting axis. For purposes of obtaining a compact construction, the mounting of the microscope is effected on that side of the microscope which faces away from the drill holding means.

It is furthermore expedient when the microscope is pivotable about an axis which is approximately parallel to the setting axis of the drill holding means, and is preferably parallel to the outlet axis of the microscope, and can be arrested in this position so that the microscope following the adjustment of the drill holding means can be correspondingly adjusted about the setting axis. Also an adjustability of the microscope at approximately a right angle with regard to the central plane of the machining zone, which central plane is approximately rectangular with regard to the feeding direction, is expedient in order to be able to compensate for possible aligning errors between the inlet axis of the microscope and the axis of the drill holding means in sharpening position.

It is particularly advantageous when the microscope is adjustable in the direction of its inlet axis and is arrestable in this position whereby a very precise setting of the sharpeners of the microscopic picture of the drill tip will be possible.

In order to be able after aligning the drill to bring the latter by means of the microscope in a single movement in feeding direction into contact with the sharpening tools, the granular size of the individual discs of the sharpening tool becomes finer from that side of said discs which face the microscope toward that side which faces away from the microscope.

It is expedient when the sharpening tools increase slightly conically in diameter in the feeding direction in order at any rate to assure that also their ranges with the finest grain will still be able to contact the drill.

A very simple alignment of the drill will be assured when the position of the microscope and the grinding position of the drill holding means are formed by the same position and when approximately in the end position pertaining to a feeding direction, the axis of the drill holding means is located in the inlet axis of the microscope. Expediently, the structural element adjustable with the microscope may be equipped with an abutment for the microscope position of the drill holding means so that independently of the respective adjustment of the microscope provided its inlet axis is parallel to the axis of the drill holding means, the latter can by abutment be brought into alignment with the inlet axis of the microscope.

In order to be able independently of outer light conditions to assure a very precise recognizing of the drill tip by the microscope, there is provided an illuminating device which is directed to the drill tip in microscope position, especially an iris diaphragm and a control device for the light intensity, preferably in the form of a transformer. The illuminating bodies of said illuminating device are preferably movable from their illuminating position to a rest position and may for instance be pivotally mounted on a part which is fixed to the microscope so that this part will not be impeded when aligning the drill on the drill abutment.

According to a preferred embodiment of the invention, for carrying out the feeding movement, exclusively the drill holding means is movable in feeding direction and is especially displaceably mounted so that the sharpening tools, the motor, and the microscope may be non-movably arranged on the machine frame with regard to the feeding movement. Expediently, the drill holding means is mounted upon a support which especially in feeding direction is movably mounted on a guiding device, especially two guiding bars of the machine frame which are located adjacent to each other. The arrangement is such that the drill holding means can by displacement of the support manually in a simple manner be moved in feeding direction, and the drill holding means can easily be aligned relative to the focus of the microscope.

According to a further development of the invention, the drill holding means includes a spindle sleeve for exchangeably receiving collets so that by aligning said collets in a simple manner, drills of different diameters can be clamped in. Expediently, in said sleeve there may be provided an ejector for the drill, which ejector is spring loaded toward the front sleeve end. By means of this ejector, after releasing the collet, the respective inserted drill can automatically be moved against the drill length abutment so that after again clamping in the collet, the drill will be precisely aligned in its longitudinal direction.

In order to permit a simple clamping and unclamping, the clamping spindle of the spindle sleeve is torward its loosened position spring loaded toward the rear and is adjustable by means of a handle at its rear end in a direction against the thrust of the spring.

In order with this design to be able to set the drill in the described manner simply by turning it about its longitudinal axis, with regard to the position of the cutting edge of the drill, the spindle sleeve preferably by means of an intermediate sleeve surrounding the same is in a bearing sleeve or the like rotatable about its central axis and/or is axially displaceable while preferably at the rear end of the bearing sleeve there is provided a friction member cooperating with the bearing sleeve so that the drill will be frictionally held in its respective adjusted rotated position.

In order to be able in one and the same clamped condition to post-sharpen the front clearance angle of all cutting edges of the drill, as a rule the two cutting edges of a spiral drill, the spindle sleeve is turnable about its central axis, especially by 180 and can be arrested in the respective turned position while preferably the bearing sleeve is rotatable in a carrier sleeve or the like and within the range of one end has an arresting member for instance in the form of an arresting ring with a diametrical slot while a spring loaded arresting pin with the pertaining end of the supporting sleeve is associated with said arresting ring. In this way, the bearing sleeve connected with the spindle sleeve by the friction element can be turned without an axial displacement.

According to a simple embodiment of the invention, the carrier sleeve is mounted on the bearing block while its pivot axis is located preferably in the center of the length of the drill holding means.

The invention is illustrated by way of example in the accompanying drawing, in which:

FIG. 1 illustrates a side view partially in section of the sharpening machine according to the invention.

FIG. 2 is a top view partially in section of FIG. 1.

FIG. 3 is an end view of FIG. 2 as seen from the righthand side of the drawing.

FIG. 4 illustrates a drill holder in a view similar to that of FIG. 2.

FIG. 5 shows a drill holder of the machine according to FIGS. 1 through 3 in axial section.

FIG. 6 shows a further sample embodiment of a machine in a view upon the working side thereof.

FIG. 7 illustrates a machine according to FIG. 6 as viewed from the left thereof.

FIG. 8 shows a top view of the machine according to FIG. 6.

FIG. 9 shows an axial section through the drill holder of the machine according to FIGS. 6 through 8.

FIG. 10 shows an axial view upon the drill tip of a spiral drill sharpened with the machine of the present invention.

Referring now to the drawings in detail, FIGS. 1-3 illustrate a tip grinding machine according to the present invention which comprises a machine frame 1 composed primarily of a square-shaped horizontal aluminum plate 2 with a rectangular frame 3 on the bottom side.

Adjacent to a corner at the top side of plate 2, there are provided two head stocks 4 with horizontal axisparallel working spindles 5 which are parallel to two plate edges. Each head stock 4 is displaceable on a vertical carriage guide 6 by means of a threaded spindle 7 located between two guiding rods connected to the legs of a U-shaped holding means, said guiding spindle 7 having an upper handle 78. The respective vertical carriage guide 6 is secured to a horizontal cylindrical carriage part 8 so as not to rotate thereon and is displaceably arranged in a corresponding carriage guide of the machine frame 1 by means of a pertaining adjusting spindle 9 in conformity with the scale so as to be able to move at a right angle to the axes of the working spindles 5. In their working position, the axes of the two working spindles 5 are located in a common approximately vertical plane, whereas as to height they are offset with regard to each other in conformity with FIG. 1.

At those sides of the head stocks 4 which face each other, a diamond grinding disc 10 is connected to the respective pertaining end of the respective working spindle 5. The diamond grinding disc 10 is formed by three individual discs 11-13 arranged adjacent to each other. The individual discs 11-13 have with both grinding discs 10 decreasing in the same sequence less coarse diamond granules so that the individual discs 11 are provided with coarse grains whereas the individual discs 12 are provided with an intermediate grain size, and the individual discs 13 are provided with a fine grain.

At those sides of the head stocks 4 which face away from each other, the pertaining end of the respective working spindle 5 has arranged thereon a pulley 14. Each pulley 14 is through the intervention of a vibration damping belt located in a belt box connected to an output pulley 15. The two output pulleys 15 are nonrotatably connected to the two ends of the motor shaft 16 of an electric motor 17 which latter is connected behind the carriage 8 on plate 2.

The belts are expediently rubber elastic so that they can adapt themselves to an adjustment of the carriage.

On that side of the head stocks 4 which face away from the carriage 8 and the motor 7, there is displaceably mounted on plate 2 in a corresponding guiding system a grinding support 19 of aluminum. This grinding support is displaceable in feeding direction indicated by the arrow 20 and, more specifically, parallel to the axes of the working spindles 5. The grinding support 19 is adapted to be manually moved back and forth. At the two ends of the support 19 there are provided abutments for setting the respective end position of the support 19 in the advancing direction indicated by the arrow 20. These abutments have associated therewith abutment spindles 21 on the machine frame. The support 19 is journalled on two cylindrical guiding bars which are located on both sides of the adjusting spindles 21 and are arranged horizontally adjacent to each other.

On the top side of the support 19 there is provided a bearing block 22 which is pivotable in conformity with a scale about a shaft 30 formed by a bearing bolt 23 and is arrestable by means of clampingscrews 24 guided in an annular groove. The bearing block 22 has on one arm extending away from the grinding discs provided a drill holder 26 which by bearing means 34 is pivotable about a horizontal axis 28 which extends at a right angle to the central axis 29. The bearing means 34 comprises a joint fork 32 connected to a carriage 31. The drill holder with a supporting sleeve 33 is in the joint fork 32 pivotable about the horizontal axis 28 by means of two pointed screws. The joint fork 32, which at both sides extends around the supporting sleeve 33, is provided on a carriage 31 which is by means of a manually operable threaded spindle 38 mounted on a carriage guide in such a way as to be displaceable parallel to the axis 29 of the drill holder 26 in sharpening position, said carriage guide 25 being provided at the upper end of the arm of the bearing block 22.

As will be seen from FIG. 5, a bearing sleeve 35 is rotatable in the supporting sleeve 33 but is axially nondisplaceable in view of the fact that the bearing sleeve 35 has a collar engaging a front end of the supporting sleeve 33 and has an arresting ring 36 screwed onto an outer thread at its rear end, said ring 36 resting against the rear end of the supporting sleeve 33. At that end face of ring 36 which faces toward the supporting sleeve 33, there is provided a diametrical slot having associated therewith a spring loaded arresting pin 37 which is axes parallel to the drill holder 26 and is arranged in the supporting sleeve 33. By turning the ring 36, which may be provided with a knurled portion, the bearing sleeve 35 may be moved into two different arresting positions around its axis 29 and offset to each other by 180.

An intermediate sleeve 77 is rotatably and axially non-displaceably arranged in the bearing sleeve 35 and protrudes beyond the rear end of sleeve 35. An annular disc 79 is screwed onto an outer thread at the rear end of intermediate sleeve 77. This disc 79 rests through a dish spring 74 upon the rear end face of ring 36 so that a possible axial play will be compensated for and the intermediate sleeve 77 can be rotated relative to the bearing sleeve 35 when a predetermined frictional force is overcome. In the arresting ring 36, adjacent to the dish spring 74, there may also be provided a ring surrounding the intermediate sleeve 77 and on its inner circumference supported on the ring 36 by means of a friction member 40. This friction member 40 may for instance be formed by a spring loaded radial pin which for preventing rotation of the ring extends through the intermediate sleeve 77 and is frictionally supported by a drilling surface of the ring 36. The ring disc 79 is nonrotatably screwed onto a sleeve-shaped handle ex tending over the rear end of ring 36, in such a way that by means of this handle 45, the intermediate sleeve 77 can be turned relative to the bearing sleeve 35.

In bearing sleeve 77 there is non-rotatably secured a clamping pipe 42 by means of a friction member 40 extending into an axial slot, said clamping pipe 42 being, however, axially displaceable. This pipe 42 is by means of a spring 80 which surrounds the same and is located in the intermediate sleeve 77, urged rearwardly relative to sleeve 77. Screwed onto the outer thread at the rear end of pipe 42 (said rear end being wider in diameter) is a sleeve 47 having arranged therein a manually operable clamping spindle 46 axially aligned with the axis 29. The clamping spindle 46 has its front end resting against the rear end of a pressure bolt 49 which is displaceably mounted in the rear end of the clamping pipe 42, while the front end of the bolt 49 is by a threaded bolt connected to the rear end of a sleeve axially displaceable in the clamping pipe 42. The sleeve 39 which is non-rotatably secured relative to the clamping pipe 42 has its front end provided with an inner cone 41 for exchangeably receiving collets or clamping pliers 76. A box nut 81 is detachably connected to an outer thread at the front end of the clamping pipe 42, said collets 76 being adapted axially to rest against the box nut 81. By turning the clamping spindle 46, the sleeve 39 and the clamping pipe 42 are adapted to be axially displaced relative to each other whereby the collets 76 may be tightened or relieved. Around the rear end of the sleeve 39 there is arranged pressure spring 44 which on one hand rests against the clamping pipe 42 and on the other hand rests against the pressure bolt 49 and thereby the sleeve 39 in such a way that the sleeve 39 is spring urged toward its releasing position and can be moved against the thrust of the spring 44 in the clamping pipe 42 by means of the clamping spindle 46.

Arranged in the sleeve 39 and with a diameter corresponding to the rear shank section is an ejector bolt 48. Between the rear shank section of bolt 48 and the threaded bolt of pressure bolt 49 in sleeve 39 is a helical pressure spring 50 by means of which the ejector 48 is urged forwardly.

At the front end of the carriage 31 there is connected a bearing 51 which carries a hairline type aligning means 52 for the front end of the clamping pipe 42 while the pipe 42 in grinding position of the drill holder 26 engages this aligning means 52. In front of this aligning means 52, there is provided a hair angle-like supporting means 55 for the front end of the drill to be sharpened which means 55 is with a square shank 56 displaceable in the bearing 51 by means of a threaded spindle 23 provided with a handle. This displacing direction when viewed in feeding direction is at an acute angle with regard to the axis 29 of the drill holder 26 and, more specifically, is located at an angle which opens toward the rear, while the two means 52 and 55 are provided below the axis of the drill holder 26 in such a way that the drill holder 27 may from its grinding position be tilted upwardly about axis 28 so that its front end will be easily accessible for exchanging the drill. Laterally arranged on carriage 31 is an abutment 53 according to FIG. 4 which is pivotable about an axis which is parallel to the drill holder in sharpening position. This shifting is possible by means of a bolt 54. The drill abutment 53 is formed by that end of a linkshaped arm which is non-rotatably connected to the front end of bolt 54. In one tilted position, the drill abutment 53 is located on the axis 29 of the drill holding means in sharpening position, whereas the abutment 53 in another pivoted position is located outside said axis adjacent the drill holder.

ln grinding position according to FIGS. 1-5, the drill holder 26 is additionally located axis parallel with regard to the inlet axis 58 of an angle microscope 57 which is located adjacent to the spindle heads 4 on the frame plate 2. The microscope 57 is connected to a carriage 59 which is displaceable by a threaded spindle in a direction parallel to the axis 58 and is guided by a carriage guiding means. This carriage guiding means is rotatable about a vertical axis 60 and' is arrestably mounted on a support 61. This pivot axis 60 is arranged in spaced relationship to the outlet axis of the microscope 57 and is parallel to axis 60 while being located in the path of movement of the tip of the drill in sharpening position. The support 61 is on a bearing 62 connected to a frame 1 rotatable about an axis 63 parallel to the feeding direction and is arrestable in its respective position while the axis 63 intersects the inlet axis 58 approximately within the range of the inlet plane of the microscope 57.

The grinding of a drill is effected in the following manner: The respective champing pliers or collet 76 is inserted into the sleeve 39 and the box nut 81 is screwed on. Subsequently, the drill is inserted and the drill holder 26 is shifted into its sharpening position while it islocated for instance between the grinding discs and the microscope 57. Thereupon, the drill abutment 53 is shifted in front of the drill holder 26 whereupon by turning the clamping spindle 46, the pliers or collet is loosened once more so that the drill is pressed by the spring loaded ejector 48 against the drill abutment 53 and in this aligned position can then be tightened by turning the clamping spindle 46.

After pivoting the drill abutment 5 3 out of the axis 29, the drill holder is by displacement of support 19 brought into alignment with the inlet axis 58 of the previously set angle microscope 57 so that the drill tip will occur as a sharp picture in the occular of the microscope 57. Then, by turning the handle 45, the sleeve 39 is turned in the bearing sleeve 35 until the cutting edges of the drill are located at the corresponding cross hairline axis of the microscope 57. Subsequently, by displacing the support 19 in the advancing direction indicated by the arrow 20, one-half of the point of the borer can be moved from right toward the left, i.e. from the side of the microscope 57, past the grinding discs 10. These two grinding discs will in view of the arrangement described above in connection with FIG. 1 form a re-entrant machining zone 68 the central plane 69 of which, which is parallel to the feeding direction, is horizontal while the drill in sharpening position will be located at an incline with regard to said central plane 69 and also at an incline with regard to the feeding direction indicated by the arrow 20. By turning the spindle 38, the clamped-in drill can be fed toward the grinding discs 10.

Following the grinding of the front clearance angle surfaces, the sleeve 39 is turned by turning the ring 36 by 180 so that now in the same manner the clearance angle surfaces pertaining to the second cutting edge of drill 70 can be ground.

In the arrangement of FIGS. 6-9, corresponding parts are designated with the same reference numerals as in FIGS. l-5 but with the index a.

Each head stock 4a is vertically adjustable on the vertical leg of an angle carrier 68 and is arrestable by means of clamping screws 7a. The supporting angles 6a are by means of their horizontal legs connected to the precision carriages 8a which by adjusting spindles 9a are individually adjustable relative to the corresponding carriage guides of the machine frame la in conformity with a scale in a direction horizontal and at a right angle to the axes of the working spindle 5a.

Arranged on both ends of the support 19a are abutment spindles 21a for setting and arresting the respective end position of the support 19a in the feeding direction indicated by the arrow 20a.

The bearing block 22a has one arm 25a which extends away from the grinding discs 10a provided with a drill holder 26a which is pivotable about two axes 27a, 28a which are at a right angle with regard to each other and to their central axis 9a. This pivot movement is possible by a cardonic joint 34a. One axis 27a is vertical and the other axis 28a is horizontal, and the three mentioned axes 27a-29a intersect in a point. The joint 34a comprises a fork-type joint 32a which with a shaft 31a is pivotable about the vertical axis 27a in arm 25a. The drill holder with a carrier sleeve 33a is pivotable about the horizontal axis 28a by means of two pointed screws. By locating the bearing block 22a on the bearing bolts-23a, the drill holder 26 is additionally pivotable about the axis 30a.

As will be seen from FIG. 9, a bearing sleeve 35a is rotatably and axially displaceably mounted in the supporting sleeve 33a. The front end of the bearing sleeve 35a forms an arresting ring 36a which at its circumference comprises two diametrically oppositely located recesses for engagement by axially protruding arresting cams 37a. These cams 37a are formed by the fact that at the front end of the supporting sleeve 33a there are provided two diametrically oppositely located cuts. By axially displacing the bearing sleeve 35a, the ring 36a can be brought out of engagement with the arresting cam 37a so that the bearing sleeve 35a can by turning be shifted by and can then again be brought into engagement with the arresting cams 37a. Directly behind-the ring 36a, on an outer thread on the front end of the supporting sleeve is guided an adjusting ring 380, said ring 36a protruding beyond the circumference of the supporting sleeve 33a so that the ring 36a when turning the adjusting ring 38a is engaged thereby and the bearing sleeve 35a is moved toward the front. The cams 37a protrude in one end position of the ring 360 beyond the front end face of the latter so that the bearing sleeve 35a can be axially adjusted to a relatively great extent relative to the supporting sleeve 33a without the ring 36a disengaging the arresting cam 37a. The rear end of the bearing sleeve 35a is in the manner of a clamping plier provided with axial slots, and in this range has an outer thread upon which a box nut 40a is guided by means of a corresponding thread section. The front sleeve-shaped end of the box nut 40a extends over the supporting sleeve 33a. In this end and extending around the bearing sleeve 35a there is provided a spring 74a which on one hand rests against the supporting sleeve 43a and on the other hand rests against the box nut 40a so that the bearing sleeve 35a is spring urged rearwardly with regard to the supporting sleeve 33a which means toward its working position. Against this spring thrust, the bearing sleeve 35a is moved during the feeding by means of the adjusting ring 36a as well as when disengaging the ring 36a. The rear end of the bearing sleeve 35a is within the range of the box nut 40a provided with axial slots in the manner of a collet, while the rear end section of this slotted part is at its outer circumference provided with a forwardly ascending cone 35a against which a corresponding inner cone of the box nut 40a rests.

In the bearing sleeve 35 there is a sleeve 39a axially displaceably and rotatably mounted, while the sleeve 39a is adapted to be tightened with regard to the bearing sleeve by tightening the box nut 40a. In this condition, the sleeve 39a can nevertheless together with the bearing sleeve 35a against the thrust of spring 34a advance to such an extent that the cams 37a will disengage the ring 36a. The front end 41a of sleeve 39a is designed for exchangeably receiving collets or the like, while in the sleeve 39a there is provided a clamping spindle 42a the front threaded end of which serves for threadedly engaging the inner thread of the respective collet 76a which inner thread is provided at the rear end of the respective collet 76a. At the rear end of the clamping spindle 42a which rear end is located outside the sleeve 39a, the spindle 42a has a collar 43a which has an enlarged diameter. Between the collar 43a and the rear end of the sleeve 39a there are provided pressure springs 44a, for instance, in the form of a dishshaped spring packet by means of which the clamping spindle 42a is resiliently pulled into the sleeve 3% so that as a result thereof the collet connected to the spindle 42a will serve for realizing a predetermined clamping force in the seat 41a of the sleeve 3%.

At the rear end of sleeve 39a there are provided two handle means 45a, 46a one of which is rigidly connected, whereas the other one 46a is pivotable about an axis 47a which is rectangular to the axis of the sleeve 39a and is angle-shaped in such a way that its transition area between the two legs engages the rear end of the spindle 42a. By compressing the two substantially parallel scissor-like handle means 45a, 46a by two fingers, the spindle 42a is against the thrust of spring 44a pressed to the front sleeve end 39a so that the collet provided in the sleeve 39a is moved into its releasing position. In the spindle 42a there is displaceably mounted an ejector bolt 48a which protrudes beyond the front end of spindle 42a. Between the rear end of the ejector bolt 48a and a counter bolt 49a screwed into the rear end of the hollow clamping spindle 42a there is provided a helical pressure spring 50a which urges the ejector bolt 40a to its front abutment limited end position.

Connected to the top side of the support 19a is an arm 51a having one of its ends provided with an anglelike hair aligning means 52a of which one leg extends vertically, whereas its horizontal leg extends away from the grinding disc a. In a pivoted position, the front end of sleeve 39a is in its aligning position 52a which is so arranged that the axis 29a of the drill holder 26a is parallel to the feeding direction a. On that side of the aligning position 52a which faces away from the mounting 34a of the drill holder 26a there is provided a drill length abutment 53a in the form of a plate which is pivotally mounted on a bolt 54a that is parallel to the feeding direction indicated by the arrow 20a. Bolt 54a is held on the aligning means 52a.

Rotatably and axially displaceably inserted into the clamping sleeve 23a of support 19a is a drill receiving prism 55a with a cylindrical shank 560 provided at its lower end. This shank 56a is adapted to be arrested by tightening the clamping sleeve 23a. The receiving prism is so aligned that with a corresponding pivot position of the drill holder 26a the drill clamped into the drill holder 26a engages the receiving prism 55a and is safely held or supported therein.

In abutment position of the drill holder 26a according to FIGS. 6-8, the drill holder 26a is furthermore arranged in an axis-parallel manner with regard to the inlet axis 58a of an angle microscope 57a which is arranged on the frame plate Zn on that side of the drill abutment 53a which facesaway from the drill holder 26a. The microscope 57a is clamped by means of a clamping shell 59a which engages a portion of the microscope 57a that is coaxial with the inlet axis 58a and does so in such a manner that the microscope can be turned about the inlet axis 58a and can be arrested in its respective position. The clamping shell 59a is connected to the horizontal displaceable carriage 61a of a cross support a in such a way that the microscope 57a can by means of adjusting spindles 62a, 63a in conformity with a scale be adjusted vertically and horizontally and each time at a right angle with regard to its inlet axis 58a. In this way the inlet axis 58a can be brought into precise alignment with the axis 29a of the drill holder 26a in abutment position of the latter. The microscope 57a has a goniometer head with a hairline cross in the optical axis and with concentric circles, while the objective part comprising the hairline cross and the concentric circles is adjustable about the optical axis by handle means 64a in conformity with a scale.

The microscope 57a has furthermore associated therewith an aximuthal illuminating device with an illuminating body 65a which is movable about a bolt 66a arranged in spaced relationship to its axis and transverse thereto from its illuminating position, in which its axis is located in a common vertical axial plane with the inlet axis 58a of the objective 570, into a rest position toward the side in such a way that it no longer will be located above the inlet axis 58a. The illuminating body 65a, which, in the abutment position of the drill holder 26a, is directed at an incline from above to the point of the drill held in the drill holder, has an adjustable iris diaphragm while the bulb of the illuminating body 65a is supplied with electric current by means of a transformer 67a located behind the microscope 57a on the frame plate 2a so that by controlling the transformer 67a, the light intensity can be varied.

The grinding of a drill is effected as follows: The respective collet is inserted into the sleeve 39a and is connected to the tensioning spindle 42a. Thereupon the drill or a measuring mandrel of the same diameter is inserted into the collet, and after adjustment of the bearing block 220 by means of the drill or the measuring mandrel, the receiving prism 55a is so adjusted that it is in precise alignment with the drill or measuring mandrel when the drill holder 26a is in its sharpening position. Subsequently, the drill holder 26a is pivoted into abutment position parallel to the feeding direction indicated by the arrow 20a, and the inserted drill is in abutment position with upwardly tilted drill abutment 53a released by compressing the handle means 45a, 46a so that the drill, in view of the force exerted by the ejector bolt 48a rests against the drill abutment 53a and thereby can be aligned as to its longitudinal direction. By releasing the handle means 45a and 46a, the drill is again tightened in its aligned position.

After pivoting the drill abutment 53a out of its axis 29a, the inlet axis 58a of the microscope 57a is by adjustment of the hairline cross support 60a aligned with the axis 29a of the drill holder 26a. By adjusting the pertaining abutment spindle 21a, the corresponding end position of the grinding support 19a is so selected that a sharp picture of the drill tip is formed in the ocular of the microscope 57a. The microscope is so adjusted that the drill will be precisely located within the concentric circles. Now, after releasing the box nut 40a, the sleeve 39a is turned in the bearing sleeve 35a until the cutting edges of the drill are located in the vertical axis of the hairline cross of the microscope 57a, whereas by tightening the box nut 40a, the sleeve 39a and thereby the drill are held in this position. Subsequently, the drill holder 26a is pivoted into sharpening position in such a way that the clamped-in drill is located in the receiving prism 55a. By the left-hand grinding disc 10 according to FIGS. 1 and 3 or the higher located grinding disc 10 according to FIG. 2, a first front clearance angle surface 72 of the drill 70 is ground which surface is adjacent the pertaining cutting edge 71, while during the same working step by the other grinding disc 10 a second front clearance angle surface adjacent to the first front clearance angle surface 72 is ground which second surface has a free surface 73 with a greater free angle than the surface 72.

After the surfaces 72, 73 pertaining to one cutting edge 71 have been ground, the sleeve 39 is in the manner described above axially displaced by means of the bearing sleeve 35a and thereby is released with regard to its rotating ability whereupon it is turned by 180 and by means of the ring 36a and cam 37 is again arrested so that now in the same manner the free surfaces pertaining to the second cutting edge of drill 70 may be ground.

With the embodiment illustrated in FIGS. 1 to 5, the drill axis, when viewed in feeding direction, is located in the grinding position in a non-changeable manner at a 50 angle with regard to the horizontal plane. Other angles with regard to the central plane 69 may in a simple manner be obtained by adjusting the grinding discs 10, in other words, by adjusting the central plane 69 of the machining zone 68.

With the embodiment illustrated in FIG. 5, between the handle means 45 and the annular disc 79 there is axially secured an adjusting nut 82 with a collar. This nut 82 is, however, rotatable and is threadedly engaging an outer thread on the rear end of the clamping pipe 42 so that a slight axial fine feeding of the clamping pipe 42 together with the sleeve 39 is possible against the thrust of the dish spring 74. For dressing the grinding discs 10, a dressing device may be arranged on the support 19. By means of such dressing device a dressing within the range of from to is possible. In this connection, the support is arrestable relative to the grinding means therefor by means of an arresting device so that the dressing tool is at a corresponding angle with regard to the feeding direction indicated by the arrow adjusted relative to the support. The dressing tool may be designed, for instance, as a dressing disc made of silicon carbide.

It is, of course, to be understood that the present invention is, by no means, limited to the particular showing in the drawings, but also comprises any modifications within the scope of the appended claims.

What is claimed is:

I. In a machine for sharpening drills, especially spiral drills; a frame, a pair of grinding disc means in said frame in adjacent substantially parallel relation and fotatable on respectively substantially coplanar axes which are offset relative to one another, drill holdermeans in said frame operable to support a drill with the axis of the drill inclined to the plane of the axes of said disc means and with the point end of the drill exposed and disposed near a plane perpendicular to the plane of the said axes of said disc means and located about midway between said axes of said disc means, and means for moving said drill holder means and said disc means relatively in said frame, said axes of said disc means being parallel and horizontal and being offset from one another in the vertical direction.

2. A machine according to claim 1 in which the drill holder means and disc means are moveable relatively in a direction parallel to the axes of said disc means to bring the point end of a drill in said drill holder means into the re-entrant grinding zone where the peripheral portions of said disc means overlap when viewed in the axial direction.

3. A machine according to claim 1 which includes a headstock in the frame rotatably supporting each said disc means, the axes of said disc means being substantially horizontal and parallel, and means for independently adjusting each headstock in said frame in first and second directions both of which are substantially perpendicular to the axis of the respective disc,

4. A machine according to claim 1 in which said disc means are closely adjacent one another, and a headstock rotatably supporting each disc means and disposed on the side of the respective disc means which faces away from the other said disc means.

5. In a machine for sharpening drills, especially spiral drills; a frame, a pair of grinding disc means in said frame in adjacent substantially parallel relation and rotatable on respectively substantially coplanar axes which are offset relative to one another, drill holder means in said frame operable to support a drill with the axis of the drill inclined to the plane of the axes of said disc means and with the point end of the drill exposed and disposed near a plane perpendicular to the plane of the said axes of said disc means and located about midway between said axes of said disc means, and means for moving said drill holder means and said disc means relatively in said frame, each said disc means being formed of a group of discs, said discs decreasing in grit size in feeding direction, and increasing in diameter in the direction of decreasing grit size.

6. A machine according to claim 1 in which said drill holder means includes means for rotating a drill therein on the axis of the drill and also includes means for rotation of the drill holder means about an axis extending at an angle to the axis of the drill and intersecting the axis of the drill near the point end of the drill.

7. A machine according to claim 1 which includes abutment means moveably mounted in said frame and operable to abut the point end of a drill in said drill holder means to locate the drill in said drill holder means.

8. In a machine for sharpening drills, especially spiral drills; a frame, a pair of grinding disc means in said frame in adjacent substantially parallel relation and rotatable on respectively substantially coplanar axes which are offset relative to one another, drill holder means in said frame operable to support a drill with the axis of the drill inclined to the plane of the axes of said disc means and with the point end of the drill exposed and disposed near a plane perpendicular to the plane of the said axes of said disc means and located about midway between said axes of said disc means, means for moving said drill holder means and said disc means relatively in said frame, means in the frame suporting said drill holder means for movement thereof parallel to the axis of a drill therein, means supporting said holder means for rotation about an axis extending at an angle to the axis of a drill in said holder means and intersecting the drill axis near the point end of the drill, means for rotating the drill in the holder means on the drill axis, means for tilting the holder means about an axis parallel to the axes of said disc means, and means for moving said holder means and said disc means relati ly in a direction parallel to the axes of said disc means.

9. A machine according to claim 1 which includes support means in said frame moveably supporting said drill holder means, and aligning means on said support means for aligning said drill holder means in grinding position.

10. A machine according to claim 1 in which said drill holder means is moveable relative to said disc means in a direction parallel to the axes of said disc means to move a drill in said holder means into and out of grinding position, and microscope means carried by said frame and located to view the point end of a drill in said holder means when the holder means is moved away from grinding position.

11. In a machine for sharpening drills, especially spiral drills; a frame, a pair of grinding disc means in said frame in adjacent substantially parallel relation and rtatable on respectively substantially coplanar axes which are offset relative to one another, drill holder means in said frame operable to support a drill with the axis of the drill inclined to the plane of the axes of said disc means and with the point end of the drill exposed and disposed near a plane perpendicular to the plane of the said axes of said disc means and located about midway between said axes of said disc means, means for moving said drill holder means and said disc means relatively in said frame, said drill holder means including a tubular portion, sleeve means in said tubular portion for receiving drill gripping collet means, ejector means in the sleeve means for ejecting drills therefrom and spring biased in drill ejecting direction, said sleeve means being rotatable in said tubular portion, a bearing sleeve and an intermediate sleeve interposed between said sleeve means and said tubular portion, and friction means interposed between said bearing sleeve and said tubular portion.

12. A machine according to claim 11 in which said bearing sleeve is arrestable in said tubular portion in positions spaced apart, said sleeve means being angularly adjustable in said bearing sleeve, and means for holding said sleeve means in angularly adjusted positions in said bearing sleeve.

PRINTER'S TRIM LINE Patent No. 5,828,160 Dated August 3, 97

Inventor(s) Georg Ernst Weng It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:

On the Title page in item "Haivera" should read Hawer'a Signed and sealed this 17th dayof December 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. I c. MARSHALL DANN Attesting Officer Commissioner of Patents FORM 304050 (10'69) USCOMM-DC wan-P69 U.S. GOVERNMENT PRINT NG OFFICE: B69- 930 

1. In a machine for sharpening drills, especially spiral drills; a frame, a pair of grinding disc means in said frame in adjacent substantially parallel relation and rotatable on respectively substantially coplanar axes which are offset relative to one another, drill holder means in said frame operable to support a drill with the axis of the drill inclined to the plane of the axes of said disc means and with the point end of the drill exposed and disposed near a plane perpendicular to the plane of the said axes of said disc means and located about midway between said axes of said disc means, and means for moving said drill holder means and said disc means relatively in said frame, said axes of said disc means being parallel and horizontal and being offset from one another in the vertical direction.
 2. A machine according to claim 1 in which the drill holder means and disc means are moveable relatively in a direction parallel to the axes of said disc means to bring the point end of a drill in said drill holder means into the re-entrant grinding zone where the peripheral portions of said disc means overlap when viewed in the axial direction.
 3. A machine according to claim 1 which includes a headstock in the frame rotatably supporting each said disc means, the axes of said disc means being substantially horizontal and parallel, and means for independently adjusting each headstock in said frame in first and second directions both of which are substantially perpendicular to the axis of the respective disc.
 4. A machine according to claim 1 in which said disc means are closely adjacent one another, and a headstock rotatably supporting each disc means and disposed on the side of the respective disc means which faces away from the other said disc means.
 5. In a machine for sharpening drills, especially spiral drills; a frame, a pair of grinding disc means in said frame in adjacent substantially parallel relation and rotatable on respectively substantially coplanar axes which are offset relative to one another, drill holder means in said frame operable to support a drill with the axis of the drill inclined to the plane of the axes of said disc means and with the point end of the drill exposed and disposed near a plane perpendicular to the plane of the said axes of said disc means and located about midway between said axes of said disc means, and means for moving said drill holder means and said disc means relatively in said frame, each said disc means being formed of a group of discs, said discs decreasing in grit size in feeding direction, and increasing in diameter in the direction of decreasing grit size.
 6. A machine according to claim 1 in which said drill holder means includes means for rotating a drill therein on the axis of the drill and also includes means for rotation of the drill holder means about an axis extending at an angle to the axis of the drill and intersecting the axis of the drill near the point end of the drill.
 7. A machine according to claim 1 which includes abutment means moveably mounted in said frame and operable to abut the point end of a drill in said drill holder means to locate the drill in said drill holder means.
 8. In a machine for sharpening drills, especially spiral drills; a frame, a pair of grinding disc means in said frame in adjacent substantially parallel relation and rotatable on respectively substantially coplanar axes which are offset relative to one another, drill holder means in said frame operable to support a drill with the axis of the drill inclined to the plane of the axes of said disc means and with the point end of the drill exposed and disposed near a plane perpendicular to the plane of the said axes of said disc means and located about midway between said axes of said disc means, means for moving said drill holder means and said disc means relatively in said frame, means in the frame suporting said drill holder means for movement thereof parallEl to the axis of a drill therein, means supporting said holder means for rotation about an axis extending at an angle to the axis of a drill in said holder means and intersecting the drill axis near the point end of the drill, means for rotating the drill in the holder means on the drill axis, means for tilting the holder means about an axis parallel to the axes of said disc means, and means for moving said holder means and said disc means relatively in a direction parallel to the axes of said disc means.
 9. A machine according to claim 1 which includes support means in said frame moveably supporting said drill holder means, and aligning means on said support means for aligning said drill holder means in grinding position.
 10. A machine according to claim 1 in which said drill holder means is moveable relative to said disc means in a direction parallel to the axes of said disc means to move a drill in said holder means into and out of grinding position, and microscope means carried by said frame and located to view the point end of a drill in said holder means when the holder means is moved away from grinding position.
 11. In a machine for sharpening drills, especially spiral drills; a frame, a pair of grinding disc means in said frame in adjacent substantially parallel relation and rotatable on respectively substantially coplanar axes which are offset relative to one another, drill holder means in said frame operable to support a drill with the axis of the drill inclined to the plane of the axes of said disc means and with the point end of the drill exposed and disposed near a plane perpendicular to the plane of the said axes of said disc means and located about midway between said axes of said disc means, means for moving said drill holder means and said disc means relatively in said frame, said drill holder means including a tubular portion, sleeve means in said tubular portion for receiving drill gripping collet means, ejector means in the sleeve means for ejecting drills therefrom and spring biased in drill ejecting direction, said sleeve means being rotatable in said tubular portion, a bearing sleeve and an intermediate sleeve interposed between said sleeve means and said tubular portion, and friction means interposed between said bearing sleeve and said tubular portion.
 12. A machine according to claim 11 in which said bearing sleeve is arrestable in said tubular portion in positions spaced 180* apart, said sleeve means being angularly adjustable in said bearing sleeve, and means for holding said sleeve means in angularly adjusted positions in said bearing sleeve. 